Generally in a valve device including an open/close valve that allows a fluid such as gas or the like to flow and also switches an open state to a sealed state or vice versa, a flow direction restriction valve mechanism may be occasionally provided. The flow direction restriction valve mechanism such as, for example, a so-called Residual pressure Valve mechanism or the like is different from the open/close valve, and restricts the flow direction of the fluid and allows gas of a predetermined pressure to remain in a Gas Cylinder (see Patent Document 1).
As shown in Patent Document 1, such a flow direction restriction valve mechanism includes a valve that is located so as to freely advance or retract to a valve open position or a valve close position and retracts toward the valve open position by a pressure of the fluid flowing in a flow path. The flow direction restriction valve mechanism also includes O-rings located at a plurality of positions. The valve advances or retracts while the air-tightness is increased, and thus the flow direction of the fluid is restricted.
Today, Cylinder Valves are diversified and are used in various environments. In such a situation, it is desired that the fluid be released with certainty and that a flow noise caused by the flow of the fluid, which is not conventionally a problem, be solved.